A variety of vascular implants are well known and widely used. Vascular filters are commonly used for filtration of blood in the inferior vena cava of human patients. Stents may be used at various locations throughout a patient's vasculature to maintain or enhance blood flow where blockage has occurred. Many vascular implants are not intended for permanent placement, and may be removed after the patient's need for them has ended or upon conclusion of the service life of the vascular implant. In the case of vascular filters patients may be equipped with a vascular filter for surgical recovery or during other relatively long periods of relative immobility associated with blood clot formation. Certain stents may become less effective over time. In either case, usual protocol is removal of the vascular implant from the patient if practicable.
Different techniques and mechanisms for the removal of vascular implants from a patient have been proposed over the years. It has been observed that endothealization of portions of certain vascular implants may occur in vivo. In general terms, endothealization is the growth of excess vascular tissue about portions of the vascular implant contacting the associated vascular wall. As a result of endothealization, portions of a vascular implant can become lodged in or against a vascular wall. This phenomenon can make it difficult to snare a hook on a vascular implant with a conventional removal device and the vascular implant may further not have a proper orientation of the vascular implant for collapsing with a sheath.